1. Field of the Invention
The present invention pertains to cutting tools for machining and finishing metal. Specifically, it pertains to cutting tools especially adapted for external or internal threading and shallow grooving of metal.
2. Brief Description of the Prior Art
In conventional machining of metal, the metal part to be machined is commonly fastened in a chuck or vise and a cutting tool fastened to a stationary tool post of the machine. The machine then rotates the part relative to the tool as the tool is fed into the part. In such machining, the tool may include an elongated bar at the end of which is attached a replaceable cutting insert. When the cutting insert is broken or worn, it may be removed or replaced with a new or sharpened cutting insert without having to replace the more expensive bar.
Many cutting bars of the prior art are provided with an anvil having a recess or groove in which the cutting insert may be received and against which the insert may be clamped. In some of these tools, the anvils are integrally formed with the bar. Since the anvil is subjected to great stress and wear, it may be broken or worn beyond further use. With tools in which the anvil is integral with the bar, this means that the entire tool, including the relatively expensive bar, must be replaced.
To eliminate replacement of cutting tool bars, two-piece bar and anvil tools have been developed in which a broken or worn anvil may be replaced without having to replace an entire bar. However, most two-piece tools do not provide the rigidity present in a one-piece bar and anvil tool. Poor rigidity characteristics result in chatter, inferior machining and more frequent breakage of cutting inserts and anvils. Furthermore, in order to provide as much rigidity as possible, the anvil of many two-piece bar and anvil tools may be so fastened to the bar as to make anvil replacement difficult and time-consuming.